Silicone defoamer composition and method for producing silicone defoamer composition by adjusting the distribution width of a zeta potential

Abstract

A silicone defoamer composition of a type which defoams by being previously added to a foaming liquid includes a composite particle group of an oil containing silicone and silica.

1 - 7 . (canceled) 
     
     
         8 . A silicone defoamer composition of a type which defoams by being previously added to a foaming liquid, the silicone defoamer composition comprising a composite particle group of an oil containing silicone as an essential component and silica, wherein
 a distribution width of a zeta potential of the composite particle group is set, characterized in that,   
       the cumulative relative frequency distribution of the zeta potential of the composite particles of the silicone defoamer composition showing a difference of 6 mV or more and 60 mV or less between the integral value of 10% and the integral value of 90%, 
       measured by laser Doppler electrophoresis method, of an aqueous dispersion liquid having a pH of 7, 
       wherein said aqueous dispersion liquid is the silicone defoamer composition aqueous dispersion, which is diluted or concentrated with water so that the composite particle concentration is 10 ppm or more and 50,000 ppm or less. 
     
     
         9 . A method for producing a silicone defoamer composition of a type which defoams by being previously added to a foaming liquid, comprising:
 a stage of selecting a type and/or an amount for each of an oil component and a silica component depending on a type of a foaming liquid;   a stage of mixing the selected oil component and silica component to prepare a silicone defoamer composition including a composite particle group of an oil containing silicone as an essential component and silica;   a stage of obtaining a sample of the silicone defoamer composition generated and measuring a distribution width of a zeta potential of the composite particle group; and   repeating the selecting stage and/or the adjusting stage, and the measuring stage until the measured distribution width of a zeta potential becomes a threshold value or more which is set, characterized in that,   
       the cumulative relative frequency distribution of the zeta potential of the composite particles of the silicone defoamer composition showing a difference of 6 mV or more and 60 mV or less between the integral value of 10% and the integral value of 90%, 
       measured by laser Doppler electrophoresis method, of the aqueous dispersion liquid having a pH of 7, 
       wherein said aqueous dispersion liquid is the silicone defoamer composition aqueous dispersion, which is diluted or concentrated with water so that the composite particle concentration is 10 ppm or more and 50,000 ppm or less. 
     
     
         10 . The method for producing a silicone defoamer composition according to  claim 9 , wherein, when the silicone defoamer composition is in a form of a compound, the zeta potential is measured while the silicone defoamer composition is in a state of a water dispersion, and when the composition is in a form of an emulsion, the silicone defoamer composition is prepared by shearing at a predetermined shear speed during production of the emulsion and the zeta potential thereof is measured in the form of emulsion. 
     
     
         11 . The method for producing a silicone defoamer composition according to  claim 9 , wherein the distribution width of the zeta potential is set to a predetermined value or less so that the silicone defoamer composition previously added to the foaming liquid is maintained in a dispersed state in the forming liquid, and the composite particles of the silicone defoamer composition are maintained in a dispersed state. 
     
     
         12 . The method for producing a silicone defoamer composition according to  claim 9 , wherein in the adjusting stage, the shear speed is selected depending on the types and/or amount of the oil component containing silicone as an essential component and the silica component selected in the selecting stage. 
     
     
         13 . The method for producing a silicone defoamer composition according to  claim 9 , wherein the stage of measuring the distribution width of the zeta potential includes a stage of making the silicone defoamer composition to be sampled have a predetermined solid concentration. 
     
     
         14 . The method for producing a silicone defoamer composition according to  claim 9 , wherein the predetermined shear speed in the preparing stage is set depending on a silicone amount/a silica amount set in the selecting stage.